For recording uilleann pipes, I actually think you'll get the most realistic sound using a stereo pair of omni mics placed at least six feet away from the instrument. The success of this approach depends in large part on the room you're using to record in, but this will capture the whole sound of the pipes as a listener would hear them. It's more like the approach often used to record classical musicians -- you can either capture the whole sound, including the space, with a pair of omnis, or else you do the spot-mic thing. You can also do a combination of these techniques, using the omnis to capture the overall sound and using spot mics on the chanter and drones. You can also use a pair of cardioids in ORTF or some other stereo array, but you'd have to move them closer to avoid bass drop-off; that's not a problem with omnis.

Some of the best recordings of solo or small ensemble classical musicians have been made with nothing more than two omni mics, recorded direct to stereo (check out Todd Garfinkle's Ma Records label for some good examples). I usually dislike the sound of close-miked pipes in recordings; the sound of the pipes is so complex and interconnected that it's hard to reproduce a realistic whole from the individual parts. Moving back and trying to capture the unified whole sound seems like a better approach; it doesn't work well for live performance due to the risk of feedback, but for recording it's worth a try.

Once again, I want to thank everyone for their input. It never ceases to amaze me the amount of experience and willingness to share that experience from the folks on this forum to newbies (1.5 years playing), like me!